The present invention relates to a core bar for steering wheels.
Typically, the core bar for steering wheels is formed, for example, by bending and welding of an iron bar material, or by integral casting of a magnesium alloy material, etc. However, the use of an iron material increases a mass of the core bar to make a weight reduction difficult. Particularly, for the type with an air bag device mounted, a steering wheel is of greater mass in its entirety. On the other hand, the use of a lightweight alloy material such as magnesium alloy enables a weight reduction, but produces difficulty of reducing a manufacturing cost due to expensive material and required finish machining for flash and surface.
Under such circumferences, JP-A 57-158158 and JP-A 60-60065 propose the structure wherein two half members each obtained by press forming a steel plate are butt-welded to form a hollow core bar. The structure having butt-welded half members allows a reduction both in mass due to use of a relatively thin steel plate and in complexity of finish machining due to application of press forming.
With the hollow core bar, it is easy to achieve a weight reduction, but difficult to improve an operation feel by restraining vibrations because a resonance point is apt to move down. Moreover, in the case of a steering wheel arranged in an inclined way, a weight reduction of the steering wheel in its entirety tends to move a weight balance to the driver""s side or downwardly. Then, a weight called dynamic damper can be mounted to the steering wheel to restrain resonance of the steering wheel produced by engine vibrations, etc., which complicates a manufacturing process, leading to increased manufacturing cost.
It is, therefore, an object of the present invention is to provide a core bar for steering wheels, which exhibits reduced weight and excellent weight balance, and allows easy achievement of anti-resonance.
The present invention generally provides a core bar for a steering wheel mounted to a steering shaft, comprising:
a first half shell;
a second half shell coupled to the first half shell,
each half shell comprising a boss portion coupled to the steering shaft, a rim portion, and a spoke portion interposed between the boss portion and the rim portion; and
an insertion received in a hollow defined by the first and second half shells.
One aspect of the present invention is to provide a core bar for a steering wheel mounted to a steering shaft, comprising:
a first half shell;
a second half shell coupled to the first half shell,
each half shell comprising a boss portion coupled to the steering shaft, a rim portion, and a spoke portion interposed between the boss portion and the rim portion; and
a weight received in a hollow formed between the first and second half shells at at least one of the boss portion, the rim portion, and the spoke portion.
Another aspect of the present invention is to provide a core bar for a steering wheel mounted to a steering shaft, comprising:
a first half shell;
a second half shell coupled to the first half shell,
each half shell comprising a boss portion coupled to the steering shaft, a rim portion, and a spoke portion interposed between the boss portion and the rim portion; and
a reinforcement arranged throughout a hollow formed between the first and second half shells at the rim portion and the spoke portion.
A further aspect of the present invention is to provide a core bar for a steering wheel mounted to a steering shaft, comprising:
a first half shell;
a second half shell coupled to the first half shell,
each half shell comprising a boss portion coupled to the steering shaft, a rim portion, and a spoke portion interposed between the boss portion and the rim portion; and
means for filling at least part of a hollow defined by the first and second half shells.